1. Field of the Disclosure
This disclosure generally relates to an optical mechanism applied to wafer scale packaging and, more particularly, to an optical mechanism using an image sensor whose semiconductor structure is sealed by transparent materials in wafer scale packaging.
2. Description of the Related Art
Presently, the image sensor chip is manufactured by cutting a die from a silicon wafer and then sealing the die with various packaging technologies such as iDip, LGA or COB technology. These packaging technologies are well known to those skilled in the art and thus details thereof are not described herein.
A common feature of the image sensor chips packaged by the above packaging technologies is that the chips are covered by a black cavity and this is a general type of the chip package nowadays. To image sensor chips, this feature can block ambient light outside the package such that an image sensor chip may be directly applied to various applications, e.g. an optical mouse, after being packaged. The image sensor chip may be directly positioned and fixed at a desired height such that it is able to detect reflected light from a table surface to perform optical navigation.
However, with the development of the semiconductor fabrication technology, the wafer scale packaging has become a mature technology. In the wafer scale packaging, it may use transparent materials, e.g. glass or epoxy, to enclose the die to form a package structure; for example, Chip Scale Package (CSP) technology, Through-Silicon Via (TSV) technology and OPLGA technology may perform the packaging process by using transparent glass or epoxy to seal the die. Therefore in the application of an image sensor chip, this kind of chip package does not have a black cavity such that ambient light outside the image sensor chip may pass through the transparent glass or epoxy to influence the operation of the image sensor chip.
According, there is a need to provide a novel optical mechanism and positioning structure capable of being applied to a wafer scale packaging.